Method of producing a pants-type diaper

ABSTRACT

A method for producing disposable undergarments is disclosed. The method generally comprises combining a first layer, comprising an elastic material sandwiched between layers of nonwoven material, and a second layer, comprising a backing material and a graphically printed applied patch of material layer.

RELATED APPLICATION

This is a continuation application of U.S. patent application Ser. No.11/083,765, filed 18 Mar. 2005, now U.S. Pat. No. 7,638,014, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.60/573,648, filed 21 May 2004, and entitled “Method of Producing aPants-Type Diaper.”

BACKGROUND OF THE INVENTION

The present invention relates to disposable undergarments and, morespecifically, to methods and apparatuses for forming disposableundergarments.

Generally, disposable undergarments such as pants-type diapers are madeup of two nonwoven layers of material with elastic strands of materialplaced between the two nonwoven layers of material thus creating anelastic web laminate. The layers of material are continuous sheets ofmaterial that are eventually cut into individual undergarment lengths.The elastic strands may be arranged and cut so that specific areas ofthe undergarment are free of elastic tension or forces. An absorbentpad, often contained within an insert or core is then also placed intothe pants-type diaper product.

To insure the pants-type diaper retains a proper shape and to hold allof the added layers of the diaper, reinforcing layers and backingmaterials are normally added to the continuous sheets of material, withthe reinforcing layers corresponding to the cut elastic strands of eachindividual blank. Each of these layers needs to be adhesively joined atsome point in the manufacturing process to the elastic web laminate toform the completed undergarment.

One such method to produce a disposable undergarment is shown inUmebayashi, U.S. Appl. No. 2003/013518. The application discloses aprocess of producing a disposable undergarment wherein a layer ofelastic material is adhered between two nonwoven layers. Further alongthe assembly process, a reinforcing material is added to the layers,followed by an absorbent pad, and then a backing layer is added to theabove combined layers. While this process will produce a disposableundergarment, it has been observed that there may potentially be moreefficient ways of producing the disposable undergarments.

SUMMARY OF THE INVENTION

The present invention provides for a method and apparatus for producingdisposable undergarments. Compared to previous designs and processes,the present invention results in less material use, less material waste,higher line speeds and higher efficiencies due to an improved overallprocess.

The process provides a single roll of nonwoven material, which is slitinto two equal segments. The segments are then routed and guided so thatthey overlap one another, with a layer of elastic material also beingfed between the two segments. The nonwoven segments and the elasticstrands are then pressed together. The resulting web laminate will beslit again, providing two separate elasticized nonwoven laminates thatwill be combined with an outer nonwoven material to form a completechassis web assembly.

An outer nonwoven backing material and one or two optional graphicappliqué panels are combined and pressed together at a separate stationalong the assembly line. A separate backing/appliqué panel web assemblywill be combined with each of the nonwoven/elastic layers. The twoseparate nonwoven/elastic layers and the backing/appliqué panel layersare then pressed and adhesively joined together to form a chassis webfor disposable undergarments. The web may have absorbent pads (typicallycontained within an insert or core) or other decorative material addedalong the process. The resulting undergarments are formed from a processthat uses less material and is more efficient than previous methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of a method of producingundergarments according to the present invention.

FIG. 1A is a cross-sectional view of the resulting web.

FIG. 1B is a cross-sectional view of the resulting web further includingan insert or core and cover strips.

FIG. 2 is a schematic representation of a section of an alternateassembly process according to the present invention.

FIG. 3 is a schematic view of a method and apparatus that may be used toproduce undergarments in accordance with the present invention.

FIG. 4 is a top planar view of a resultant layer formed according to thepresent invention.

FIG. 5 is a finished disposable undergarment produced according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Although the disclosure hereof is detailed and exact to enable thoseskilled in the art to practice the invention, the physical embodimentsherein disclosed merely exemplify the invention, which may be embodiedin other specific structures. While the preferred embodiment has beendescribed, the details may be changed without departing from theinvention.

FIG. 1 shows a diagrammatic illustration of an embodiment of the presentinvention. A system 10 for producing the chassis assembly for disposableundergarments is shown. FIG. 1 shows two segments or layers of nonwovenmaterial 100 a and 100 b, slit by slitter 101 from a common roll 100,preferably having equal widths, fed into the system 10. A roll or layeror strands of elastic material 102 are also fed into the system 10, withthe elastic material 102 being fed intermediate of the two nonwovenlayers of material 100 a and 100 b. An adhesive applicator 104 appliesan adhesive coating to one of the layers of nonwoven material 100 a or100 b. Alternatively, the adhesive coating may be applied to bothnonwoven layers 100 a and 100 b, or to the elastic material 102. Thedesign of the nonwoven materials 100 a and 100 b and the elasticmaterial 102 should determine where and how the adhesive applicatorapplies an adhesive to the system 10, and any arrangement should not beconsidered a limiting factor. The adhesive applicator 104 may supply ahot melt adhesive or any other suitable adhesive that will sufficientlyadhere the elastic material 102 to the layers of nonwoven material 100 aand 100 b. The nonwoven layers 100 a and 100 b and the elastic material102 are then fed through a pair of pressing rollers 106 a to securelybind the elastic material 102 to the nonwoven layers 100. The nonwovenlayers 100 a and 100 b and the elastic material 102 are next fed throughan edge folder 106 b. After being pressed together and having the edgesfolded, the layers 100 a, 100 b, and 102 are then fed through a slittingstation 107 a and a spreader assembly 107 b to position these separateelasticized web laminates on new process lines. These newly centeredwebs are then each fed through a cutting roller 108 and an anvil roller110. The anvil roller 110 supplies resistance for the cutting roller108, which has cutting means 112 located on its exterior surface. Thecutting means 112 cuts through one layer of the nonwoven layers 100 andsevers the elastic material 102 positioned between the nonwoven layers.The cutting means 112 may cut both nonwoven layers 100 a and 100 b, butit is preferable that only layer 100 a is severed. Layer 100 a refersonly to the layer near the cutting means 112 and should not be limitedto any spatial orientation. A resultant web of material 114 is formedhaving predetermined individual areas with and without elastic materialon or elastic forces in the web 114.

Still referring to FIG. 1, a second feed area is located on the rightside of the schematic. A web of backing material 116 is fed into thesystem 10. Also, a web of graphically printed material 118 is fed intothe system 10. An adhesive applicator 120, similar to the adhesiveapplicator 104, will apply an adhesive material to the graphicallyprinted material 118. The graphically printed material 118 will proceedthrough a slitting station 121 a and a web spreader assembly 121 bbefore encountering a cutting roll 122 and a pressing or transfer roll124. The pressing/transfer roll 124, along with another transferringroll 126, will transfer the graphically printed material 118 onto thebacking material 116. Further along the process, a pair of pressingrolls 129 will assist in binding the backing material 116 and thegraphically printed material 118 together, resulting in a second web ofmaterial 128. Provided the backing material 116 and the graphicallyprinted material 118 are adequately secured to one another after passingthe transferring roll 126, the pressing rolls 129 may not be necessaryin the system. It should be noted that the graphically printed material118 can be slit and separated prior to or after the adhesive applicator120 so that ultimately graphics can appear on both front and back of thefinished pants type diaper.

A third adhesive applicator 130, similar to the previously mentionedadhesive applicators 120 and 104, applies an adhesive to the second webof material 128 after the graphically printed material and the backingmaterial have been combined. The second web of material 128 and theresultant webs of material 114 are then pressed together and the edgesare folder at second edge folder 115, forming a final web 132 thatcomprises all of the previous layers. The final web 132 as shown in FIG.1A will proceed for further modifications, such as adding decorativematerial, absorbent material, or cutting of leg holes, if not previouslyadded, folding, sealing and severing the web 132 into individualundergarments. As shown in FIG. 1B, the final web may have an insert orcore 140 placed between the inwardly folded edges of the nonwovenmaterial 100. In addition, one or more cover strips 142 may be adheredto conceal the junction of the edges and the insert.

FIG. 2 is an alternate schematic representation of the introductory feedarea of the present system. A single preliminary layer of nonwovenmaterial 40 provides a starting point for the system 10. The preliminarylayer 40 proceeds towards a first slitting device 42, which will cut thepreliminary layer 40 into a pair of feeder layers 50. The feeder layers50 each form the basis of an eventual final web 132 (see FIGS. 1A and4). As previously stated, the preliminary layer 40 provides for twosystems 10 shown in FIG. 1, as understood in the present invention torun concurrently. The feeder layer 50 proceeds towards a second slittingdevice 52, which will cut and slit the feeder layer 50 into the nonwovenlayers 100 a and 100 b, preferably with the nonwoven layers 100 a and100 b having equal widths. The four nonwoven layers, two layers 100 aand two layers 100 b, are separated and fed into the system 10 onopposing sides of the two elastic layers 102, with a nonwoven layer 100a and 100 b supplied for each elastic layer 102. As shown the adhesiveapplicator 104 applies an adhesive to one of the nonwoven layers 100that results from each of the feeder layers 50 after being slit by thesecond slitting device 52. However, it is possible the adhesiveapplicator 104 may provide adhesive prior to the layers proceeding tothe pressing roller 106.

Still referring to FIG. 2, the pressing roller 106 and the cuttingroller 108 are shown to be sufficiently wide enough so that singlerollers may be used to process all of the layers. While this ispreferred for efficiency and cost purposes, it is possible to haveindividual rollers for each set of combined layers and still fall withinthe scope of the present invention.

FIG. 3 provides a further schematic representation of a full widthchassis assembly fabrication system 10 similar to that shown in FIG. 1.Like elements are denoted by like reference numerals. The nonwovenlayers 100 a and 100 b originate from the single feeder layer ofmaterial 100. The feeder layer 100 proceeds towards the second slittingdevice 101, which will cut and slit the feeder layer 100 into thenonwoven layers 100 a and 100 b, preferably with the nonwoven layers 100a and 100 b having equal widths, which are then separated and fed intothe system 10 on opposing sides of the elastic layer 102. The elasticlayer 102 is a stretched sheet, which may be made up of threads, scrims,elastic sheets, or other elastic materials that will provide elasticproperties for the undergarments. An adhesive material is applied to thenonwoven layers 100 a and 100 b and the elastic layer 102, as previouslydescribed in FIG. 1. Likewise, as discussed with respect to FIG. 2,adhesive material may be applied to anywhere before the layers 100 a,100 b, and 102 encounter the pressing roll 106. The layers 100 a, 100 b,and 102 are fed through the pressing rolls 106. Each respective web isthen fed through each cutting roller 108. The cutting roller 108 is notnecessarily limited to devices that cut the elastic material 102, butalso may include die presses, ultrasonic methods, or heated presses thatwill remove the elastic material 102 (or the elastic forces) from aspecific predetermined area 54 on the nonwoven layers 100.

Still referring to FIG. 3, the backing material 116 and the graphicallyprinted material 118 are shown being fed together through the transferroll 124 and the pressing roll 126. As previously noted with respect toFIG. 1, the web of graphically printed material 118 passes the cuttingroll 122. The cutting roll 122 will cut the graphically printed materialinto specific graphically printed sections 56 of predetermined area. Theweb of graphically printed material 118 is preferably fed into thesystem at a slower rate than that of the backing material 116, forinstance by controlling the speed of the feed roll for material 118. Aslower feed rate allows the graphically printed sections 56 to be cut toa shorter length and spaced apart from one another in a distance thatwill correspond to one graphically printed section per an individualundergarment. Each of the resulting graphically enhanced sections 56will be approximately the same size as that of the area 54 having theelastic material 102 removed. Preferably, the graphically enhancedsections 56 will be slightly larger than the areas 54, to insure thatthe graphically enhanced section adequately covers the elastic forcefree area 54. The second web of material 128 exiting the transfer roll124 and the press roll 126 displays such an arrangement. The final webof material 132 includes the graphically enhanced sections 56 alignedwith the areas where the elastic material 102 was removed. It shouldagain be noted that the graphically printed material 118 can be slit andseparated prior to or after hot melt application so that graphics canappear on both front and back of the finished pants-type diaper.

The final web of material 132 can be viewed in FIG. 4. As shown, thefinal web 132 has leg holes 60 cut from the final web 132 and, also, anabsorbent layer of material 62 added to the final web 132. It isunderstood that the leg holes 60 and the absorbent layer 62 may be addedat varying positions during the undergarment formation process. Thegraphically enhanced sections 56 a correspond to the areas 54 a, whichare located where the elastic layers 102 a are positioned on the finalweb 132. FIG. 4 shows the elastic layers 102 b as non-continuouselements that are interrupted by additional non-adhered areas 54 b andthe graphically enhanced sections 56 b. It will be understood thatnon-adhered sections 54 b and graphically enhanced sections 56 b couldbe omitted on the elastic layers 102 b and still fall within the scopeof the present invention. It will also be understood that the final web132 may be designed without the elastic layer 102 b present.

A single resultant undergarment 70 is shown in FIG. 5. The undergarment70 has the graphically enhanced sections 56 a and 56 b displayed. Adecorative design 72 may appear on the graphically enhanced section 56a. The undergarment is shown with a graphically enhanced section 56 alocated on a front side 74 of the undergarment 70 and a second section56 b located on the opposite side 76 of the undergarment 70. If desired,only one graphically enhanced section may be formed in each undergarment70. In the case of two graphically enhanced sections 56 a and 56 b, thesystem would operate as previously shown and described with respect tothe previous figures, except that the graphically printed web ofmaterial 118 would be divided into separate strips, or possibly two websof material 118 would be fed into the system. Likewise, when the elasticmaterial 102 passes the cutting roller 108, the cutting roller 108 wouldremove a second section of elastic material 102 that would correspond tothe backside 76 of the undergarment 70.

The method described and shown has advantages over prior art designs.Providing a layer consisting of nonwoven material and elastic materialseparate from a layer consisting of the backing material and thegraphically enhanced material provides for a system that improvesoverall process control as compared to prior art designs. Generally, theprocess adheres together two separate layers to form a portion of thefinal garment web. Prior designs have a first layer, with everysubsequent layer of material adhered separately to the first layer.Thus, each time a new layer is added, such as the backing material orthe graphically enhanced material, another possible chance formisalignment or nonadherance arises. The present method minimizes thepotential for such errors, which also leads to higher line speeds andmaterial savings.

The foregoing is considered as illustrative only of the principles ofthe invention. Furthermore, since numerous modifications and changeswill readily occur to those skilled in the art, it is not desired tolimit the invention to the exact construction and operation shown anddescribed. While the preferred embodiment has been described, thedetails may be changed without departing from the invention, which isdefined by the claims.

1. A method of making an undergarment, the method comprising the stepsof: a. providing an elastic sheet material and first and secondoppositely disposed layers of nonwoven fabric material; b. adhering saidelastic material to said facing sides of said first and second layers ofnonwoven fabric material; c. severing a pre-selected portion of saidelastic material; d. providing a discontinuous section of graphicallyprinted material, said section having a predetermined area exceeding thearea of said severed portion of said elastic material; e. providing asheet of backing material; f. adhering said graphically printed materialto one side of said sheet of backing material; g. merging and adheringsaid backing material and said graphically printed material to saidsecond nonwoven layer of fabric material wherein said graphicallyprinted material is aligned with and extending over said severed portionof said elastic material; and h. folding a portion of said second layerof nonwoven fabric over a portion of said first layer of nonwoven fabricthereby forming an assembled chassis web.
 2. The method according toclaim 1 further including the step of adhering an absorbent pad to saidassembled chassis web.
 3. The method according to claim 1 furtherincluding the steps of: providing a feeder layer of nonwoven material;and slitting said feeder layer of nonwoven material to form said firstand second layers of nonwoven material.
 4. A method of making anundergarment, the method comprising the steps of: a. providing anelastic sheet material and first and second oppositely disposed layersof nonwoven fabric material; b. adhering a first portion of said elasticmaterial to said facing sides of said first and second layers ofnonwoven fabric material to define a second non-adhering portion of saidelastic sheet material; c. severing said second portion of said elasticmaterial from said first portion of said elastic material; d. providinga discontinuous section of graphically printed material, said sectionhaving a predetermined area exceeding the area of said secondnon-adhering portion of said elastic material; e. providing a sheet ofbacking material; f. adhering said graphically printed material to oneside of said sheet of backing material; g. merging and adhering saidbacking material and said graphically printed material to said secondnonwoven layer of fabric material, and wherein said graphically printedmaterial is aligned with and extending over said non-adhering portion ofsaid elastic material; and h. folding a portion of said second layer ofnonwoven fabric over a portion of said first layer of nonwoven fabricthereby forming an assembled chassis web.
 5. The method according toclaim 4 further including the step of adhering an absorbent pad to saidassembled chassis web.
 6. The method according to claim 4 furtherincluding the steps of: providing a feeder layer of nonwoven material;and slitting said feeder layer of nonwoven material to form said firstand second layers of nonwoven material.